<html xmlns="http://www.w3.org/1999/xhtml">

<body>

<div><math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mfenced open="[" close="]">
    <mtable id="table" rowlines="dashed">
      <mtr>
         <mtd><mi>x</mi></mtd>
         <mtd><mi>y</mi></mtd>
      </mtr>
      <mtr>
         <mtd><mi>z</mi></mtd>
         <mtd><mi>w</mi></mtd>
      </mtr>
    </mtable>
  </mfenced>
</math></div>        

</body>

</html>
